JEFFERSON CITY, Mo. (AP) -- Missouri's education commissioner provided advice to a group crafting a ballot proposal that would end tenure protections for public school teachers and instead make their employment contingent on student achievement.

State email records show commissioner Chris Nicastro met with an advocate of the ballot initiative more than a year ago, suggested specific wording and reviewed a final draft of the initiative before it was filed this March with the secretary of state's office.

Nicastro's involvement is detailed in emails released by the Department of Elementary and Secondary Education in response to a Sunshine Law request filed by the Missouri chapter of the National Education Association. The teachers' union, which opposed the initiative, provided the emails to The Associated Press.

The group said Nicastro's involvement went beyond what was appropriate for a nonpartisan appointee of the State Board of Education.

Nicastro said Wednesday that she has no position on the initiative but provided the group information just as she would with anyone proposing a change in state law.

But Mark Jones, the political director for the MNEA, said, "What you're seeing here is simply a level of collaboration and collusion that is just concerning."

The initiative campaign has been financed by retired investment mogul and political activist Rex Sinquefield, who has tried unsuccessfully to advance similar ideas in the state Legislature. The initiative would end tenure protections for teachers and other certified school staff by limiting their contracts to three year. Starting in July 2015, all public school districts would need to use a staff evaluation that relies on "student performance data" to guide decisions on promoting, demoting, firing and paying personnel.

A financial summary developed by the state auditor's office puts no specific price tag on the proposal but says "signification potential costs may be incurred" by the state or local districts if new evaluation tools must be created.

A Cole County judge in September rejected a legal challenge to the initiative's summary and cost estimate. A state appellate court on Monday dismissed an attempt to appeal that ruling, because the request was filed too late.

Supporters plan to begin gathering the roughly 160,000 signatures of registered voters needed to qualify the proposed constitutional amendment for the November 2014 ballot, said Kate Casas, state policy director for the Children's Education Council of Missouri, one of the groups backing the initiative.

Emails show Casas met with Nicastro a year ago to discuss the proposal. In an email sent Oct. 12, 2012, Casas thanked Nicastro "for spending so much time meeting with me" and attached a revised version of the initiative "based on our conversation."

"As you will see, we are taking the language you suggested about evaluations and are removing the word teacher so that we are talking about certified staff," Casas wrote in the email. Casas then referenced other wording that wasn't changed, even though she said Nicastro told her some members of State Board of Education may not like it.

"As we talked about yesterday, our primary concern at this point is the fiscal note and (we) are hopeful that with the language you see attached here, DESE would advise the auditors office that there would be little to no cost to the state to implement this IP," Casas wrote, referring to the initiative petition.

A little over an hour after receiving the email, Nicastro forwarded it to her chief of staff Robin Coffman and general counsel Mark Van Zandt with a note atop saying: "For closed session Monday. Mark, please bring hard copies for all. Do not post." The forwarded email left out the paragraph in Casas' original message that referenced the specific wording suggestions made by Nicastro.

The State Board of Education met Oct. 15-16, 2012. Nicastro said Wednesday that she doesn't recall why she might have removed part of the email or whether the initiative was discussed in a closed session. The agenda and minutes include no mention of the proposed initiative on teacher evaluations.

On March 1, Casas again emailed Nicastro a revised draft of the initiative while seeking her opinion on whether the wording about teacher evaluations aligned with a model the department already was developing.

"I don't think that's improper," Casas told the AP. "I do think that's what the role of these officials should be."

After the initiative was filed March 15, the auditor's office made a routine request for a cost estimate from the education department. Agency records show that a staff member originally proposed saying there was the "potential for significant unknown costs" to local school districts, but Nicastro changed that to say "cost unknown."

By contrast, the MNEA suggested to the auditor's office that the initiative could cost $5.5 billion to implement and an additional $93 million annually to develop and administer standardized tests for every subject at every grade level for use in staff evaluations.

Other ballot initiative supporters also have occasionally sought advice from government officials. A spokesman for a proposed transportation sales tax said supporters met with the general counsel of the Department of Transportation before filing that initiative this fall. But the sponsor of a proposed minimum wage increase said she didn't first screen the initiative with the state Department of Labor and Industrial Relations.